Autosomal dominant cerebellar ataxia type I in Martinique (French West Indies): genetic analysis of three unrelated SCA2 families.

摘要: Autosomal dominant cerebellar ataxias (ADCAs) are a group of neurodegenerative disorders that clinically and genetically heterogeneous. We report here genetic linkage study, with five chromosome 12q markers, three Martinican families ADCA type I, for which the spinocerebellar ataxia 1 (SCA1) locus was excluded. Linkage to SCA2 demonstrated maximal lod score 6.64 at θ = 0.00 marker D12S354. Recombinational events observed by haplotype reconstruction is located in an approximately 7-cM interval flanked D 12S 105 D12S79. Using thez max-l method, multipoint analysis further reduced candidate region 5 cM. Two shared common loci spanning 7 cM, suggests founder effect, whereas different segregated disease third family. Finally, mean anticipation 12 ± 14 years found parent-child couples, no parental sex suggesting might be caused expanded unstable triplet repeat.